Vibration dampening grip cover for the handle of an implement

ABSTRACT

A vibration dampening grip cover for the handle of an implement is preferably of multilayer laminate form having an inner vibration dampening layer and an outer gripping layer. A further inner force dissipating stiffening layer is included in the laminate. In a variation of the invention a grip cover is in the form of a sleeve which fits over the end of an implement handle. The sleeve terminates in a peripherally outward knob. The sleeve may be of a single layer made from vibration dampening material or may be a multilayer laminate.

BACKGROUND OF THE INVENTION

[0001] U.S. Pat. Nos. 5,653,643 and 5,944,617 disclose vibrationabsorbing material which is particularly useful when applied to thegripping area of the handle of some type of implement such as a golfclub or various types of other athletic equipment or tools. The materialdescribed in those patents is of single layer form having certaincharacteristics with regard to its friction, vibration dampening andhardness features. It would be desirable if variations could be providedfor such material which would enhance the characteristics of thematerial without significantly resulting in a material which is ofimpractical thickness. Ideally, such material should provide a stingfree grip which could be readily adapted to the handle of various typesof implements such as athletic equipment, tools and handlebars.

SUMMARY OF THE INVENTION

[0002] An object of this invention is to provide a variation of thetechniques described in U.S. Pat. Nos. 5,653,643 and 5,944,617.

[0003] In accordance with one practice of this invention a molded sleeveis utilized for fitting over the handle of an implement. The sleeve isopen at one end to facilitate the sleeve fitting around the handle. Theother end of the sleeve includes an outwardly extending peripheral knobwhich acts as a stop to minimize any tendency of the user's hand to slipfrom the handle. By making the knob of vibration dampening material, theknob also cooperates in achieving a sting free grip. The sleeve itselfcould be made of single layer form from the type of material shown anddescribed in U.S. Patent Nos. 5,653,643 and 5,944,617. Alternatively,the sleeve could be a multilayer laminate having an inner layer of suchtype of material of the aforenoted patents and an outer layer of tackymaterial which could be the same as or different from the inner layer.

[0004] In a preferred practice of the invention there is at least oneintermediate layer which is preferably made of a force dissipating orstiffening material such as aramid fibers.

[0005] The invention may also be practiced where the sleeve or coverdoes not necessarily include a knob and wherein the cover is amultilayer laminate as described above.

THE DRAWINGS

[0006]FIG. 1 is an elevational view of a baseball bat having a cover inthe form of a sleeve on the handle area in accordance with thisinvention;

[0007]FIG. 2 is an enlarged fragmental cross-sectional view of the batand sleeve shown in FIG. 1;

[0008]FIG. 3 is a schematic diagram showing the results in theapplication of shock forces on a cover in accordance with thisinvention;

[0009]FIG. 4 is a view similar to FIG. 2 showing an alternative sleevemounted on a different implement;

[0010]FIG. 5 is a view similar to FIGS. 2 and 4 showing still yetanother form of sleeve in accordance with this invention;

[0011]FIG. 6 is a cross-sectional longitudinal view showing analternative cover in accordance with this invention mounted on a furthertype of implement;

[0012]FIG. 7 is a cross-sectional end view of yet another cover inaccordance with this invention;

[0013]FIG. 8 is an elevational view of a hammer incorporating anabrasive dampening handle in accordance with this invention;

[0014]FIG. 9 is an elevational view showing a portion of a handlebarincorporating a vibration dampening cover in accordance with thisinvention;

[0015]FIG. 10 is a view similar to FIG. 9 of yet another practice ofthis invention; and

[0016] FIGS. 9-12 are plan views of various forms of the intermediateforce dissipating layer which is used in certain practices of thisinvention.

DETAILED DESCRIPTION

[0017] The present invention is directed to a cover for the handle of animplement. The cover is made of a vibration dampening or vibrationabsorbing material which may include as one layer the type of materialdisclosed in U.S. Pat. Nos. 5,653,643 and 5,944,617. All of the detailsof those patents are fully incorporated herein not only with regard tothe materials, but also with regard to the devices to which the materialmay be applied, as well as other disclosures in those patents.

[0018] FIGS. 1-2 illustrate one practice of this invention. As showntherein a cover in the form of a sleeve 10 is mounted on the handle orlower portion 18 of a baseball bat 10. Sleeve 10 is premolded so that itcan be fit onto the handle portion of the bat 12 in a quick andconvenient manner. This can be accomplished by having the sleeve 10 madeof a stretchable or resilient material so that its upper end 14 would bepulled open and could be stretched to fit over the knob 17 of the bat12. Alternatively, or in addition, sleeve 10 may be provided with alongitudinal slit 16 to permit the sleeve to be pulled at leastpartially open and thereby facilitate snapping the sleeve 10 over thehandle 18 of the bat 12. The sleeve would remain mounted in place due tothe tacky nature of the sleeve material and/or by the application of asuitable adhesive on the inner surface of the sleeve and/or on the outersurface of handle 18.

[0019] A characterizing feature of sleeve 10, as illustrated in FIGS.1-2, is that the lower end of the sleeve includes an outwardly extendingperipheral knob 20. Knob 20 could be a separate cap snapped onto orsecured in any other manner to the main portion of sleeve 10.Alternatively, knob 20 could be integral with and molded as part of thesleeve 10.

[0020] In a broad practice of this invention, sleeve 10 is of a singlelayer made from the type of material described in U.S. Pat. Nos.5,653,643 and 5,944,617. Such material is a vibration dampeningmaterial, an example being a silicone gel such as used for caulkingpurposes. The material would have the appropriate hardness and vibrationdampening characteristics. The outer surface of the material would betacky having high friction characteristics.

[0021] Alternatively, the sleeve 10 could be formed from a two layerlaminate where the vibration absorbing material forms the inner layerdisposed against the handle, with a separate tacky outer layer made fromany suitable high friction material such as a thermoplastic materialwith polyurethane being one example. Thus, the two layer laminate wouldhave an inner elastomer layer which is characterized by its vibrationdampening ability, while the main characteristic of the outer elastomerlayer is its tackiness to provide a suitable gripping surface that wouldresist the tendency for the user's hand to slide off the handle. Theprovision of the knob 20 also functions both as a stop member tominimize the tendency for the handle to slip from the user's hand and tocooperate in the vibration dampening affect.

[0022]FIG. 2 illustrates the preferred form of multilayer laminate whichincludes the inner vibration absorbing layer 22 and the outer tackygripping layer 24 with an intermediate layer 26 made of a stiffeningmaterial which dissipates force. If desired layer 26 could be innermostand layer 24 could be the intermediate layer. A preferred stiffeningmaterial would be aramid fibers which could be incorporated in thematerial in any suitable manner as later described with respect to FIGS.11-14.

[0023]FIG. 3 schematically shows what is believed to be the affect ofthe shock forces from vibration when the implement makes contact such asfrom the bat 12 striking a ball. FIG. 3 shows the force vectors inaccordance with a three layer laminate, such as illustrated in FIG. 2,wherein elastomeric layers 22,24 are made of a silicone material of thetype described in U.S. Pat. Nos. 5,653,643 and 6,944,617. Theintermediate layer 26 is an aramid layer made of Kevlar® fibers. Theinitial shock or vibration is shown by the lateral or transverse arrows28 on each side of the sleeve laminate 10. This causes the elastomericlayers 22,24 to be compressed along the arc 30. The inclusion of theintermediate layer 26 made from a force dissipating material spreads thevibration longitudinally as shown by the arrows 32. The linear spread ofthe vibration causes a rebound effect which totally dampens thevibration.

[0024] Laboratory tests were carried out at a prominent university toevaluate various grips mounted on baseball bats. In the testing,baseball bats with various grips were suspended from the ceiling by athin thread; this achieves almost a free boundary condition that isneeded to determine the true characteristics of the bats. Two standardindustrial accelerometers were mounted on a specially fabricated sleeveroughly in positions where the left hand and the right hand would gripthe bat. A known force was delivered to the bat with a standardcalibrated impact hammer at three positions, one corresponding to thesweet spot, the other two simulating “miss hits” located on themid-point and shaft of the bat. The time history of the force as well asthe accelerations were routed through a signal conditioning device andwere connected to a data acquisition device. This was connected to acomputer which was used to log the data.

[0025] Two series of tests were conducted. In the first test, a controlbat (with a standard rubber grip, WORTH Bat—model #C405) was compared toidentical bats with several “Sting-Free” grips representing practices ofthe invention. These “Sting-Free” grips were comprised of two layers ofpure silicone with various types of Kevlar® inserted between the twolayers of silicone. The types of Kevlar® used in this test werereferenced as follows: “005”, “645”, “120”, “909”. Also, a bat with justa thick layer of silicone but no Kevlar® was tested. With the exceptionof the thick silicone (which was deemed impractical because of theexcessive thickness), the “645” bat showed the best reduction invibration magnitudes.

[0026] The second series of tests were conducted using EASTON Bats(model #BK8) with the “645” Kevlar® in different combinations withsilicone layers: The first bat tested was comprised of one bottom layerof silicone with a middle layer of the “645” Kevlar® and one top layerof silicone referred to as “111”. The second bat test was comprised oftwo bottom layers of silicone with a middle layer of Kevlar® and one toplayer of silicone referred to as “211”. The third bat tested wascomprised of one bottom layer of silicone with a middle layer of Kevlar®and two top layers of silicone referred to as “112”. The “645” bat withthe “111” configuration showed the best reduction in vibrationmagnitudes.

[0027] In order to quantify the effect of this vibration reduction, twocriteria were defined: (I) the time it takes for the vibration todissipate to an imperceptible value; and, (2) the magnitude of vibrationin the range of frequencies at which the human hand is most sensitive.

[0028] The sting-free grips reduced the vibration in the baseball batsby both quantitative measures. In particular, the “645” Kevlar® in a“111” configuration was the best in vibration reduction. In the case ofa baseball bat, the “645” reduced the bat's vibration in about ⅕ thetime it took the control rubber grip to do so. The reduction in peakmagnitude of vibration ranged from 60% to 80%, depending on the impactlocation and magnitude.

[0029] It was concluded that the “645” Kevlar® grip in a “111”combination reduces the magnitude of sensible vibration by 80% that isinduced in a baseball bat when a player hits a ball with it. This wasfound to be true for a variety of impacts at different locations alongthe length of the bat. Hence, a person using the “Sting-Free” grips ofthe invention would clearly experience a considerable reduction in thesting effect (pain) when using the “Sting-free” grip than one would witha standard grip.

[0030] In view of the above tests a particularly preferred practice ofthe invention involves a multilayer laminate having an aramid such asKevlar®, sandwiched between layers of pure silicone. The above indicatedtests show dramatic results with this embodiment of the invention. Asalso indicated above, however, the laminate could comprise othercombinations of layers such as a plurality of bottom layers of siliconeor a plurality of top layers of silicone. Other variations include arepetitive laminate assembly wherein a vibration dampening layer isinnermost with a force dissipating layer against the lower vibrationdampening layer and then with a second vibration dampening layer overthe force dissipating layer followed by a second force dissipatinglayer, etc. with the final laminate layer being a gripping layer whichcould also be made of vibration dampening material. Among theconsiderations in determining which laminate should be used would be thethickness limitations and the desired vibration dampening properties.

[0031] The various layers could have different relative thicknesses.Preferably, the vibration dampening layer, such as layer 22, would bethe thickest of the layers. The outermost gripping layer, however, couldbe of the same thickness as the vibration dampening layer, such as layer24 shown in FIG. 2 or could be a thinner layer since the main functionof the outer layer is to provide sufficient friction to assure a firmgripping action. A particularly advantageous feature of the inventionwhere a force dissipating stiffening layer is used is that the forcedissipating layer could be very thin and still achieve its intendedresults. Thus, the force dissipating layer would preferably be thethinnest of the layers, although it might be of generally the samethickness as the outer gripping layer. If desired the laminate couldalso include a plurality of vibration dampening layers (such as thinlayers of gel material) and/or a plurality of stiffening forcedissipating layers. Where such plural layers are used, the variouslayers could differ in the thickness from each other.

[0032] FIGS. 1-2 show the use of the invention where the sleeve 10 ismounted over a baseball bat 12 having a knob 17. The same general typestructure could also be used where the implement does not have a knobsimilar to a baseball bat knob. FIG. 4, for example, illustrates avariation of the invention wherein the sleeve 10A would be mounted onthe handle 18A of an implement that does not terminate in any knob. Suchimplement could be various types of athletic equipment, tools, etc. Thesleeve 10A, however, would still have a knob 20A which would include anouter gripping layer 24A, an intermediate force dissipating layer 26Aand an inner vibration dampening layer 22A. In the embodiment shown inFIG. 4, the handle 18A extends into the knob 20A. Thus, the inner layer22A would have an accommodating recess 34 for receiving the handle 18A.The inner layer 22A would also be of greater thickness in the knob areaas illustrated.

[0033]FIG. 5 shows a variation where the sleeve 10B fits over handle 18Bwithout the handle 18B penetrating the knob 20B. As illustrated, theouter gripping layer 24B would be of uniform thickness both in thegripping area and in the knob. Similarly, the intermediate forcedissipating layer 26B would also be of uniform thickness. The innershock absorbing layer 22B, however, would completely occupy the portionof the knob inwardly of the force dissipating layer 26B since the handle18B terminates short of the knob 20B.

[0034]FIG. 6 shows a variation of the invention where the gripping cover36 does not include a knob. As shown therein, the gripping cover wouldbe mounted over the gripping area of a handle 38 in any suitable mannerand would be held in place either by a previously applied adhesive ordue to the tacky nature of the innermost vibration dampening layer 40 ordue to resilient characteristics of the cover 36. Additionally, thecover might be formed directly on the handle 38. FIG. 8, for example,shows a cover 36B which is applied in the form of tape.

[0035] As shown in FIG. 6 the cover 36 includes one of the laminatevariations where a force dissipating layer 42 is provided over the innervibration dampening layer 40 with a second vibration dampening layer 44applied over force dissipating layer 42 and with a final thin grippinglayer 46 as the outermost layer. As illustrated, the two vibrationdampening layers 40 and 44 are the thickest layers and may be of thesame or differing thickness from each other. The force dissipating layer42 and outer gripping layer 44 are significantly thinner.

[0036]FIG. 7 shows a cover 36A mounted over a hollow handle 38A which isof non-circular cross-section. Handle 38A may, for example, have theoctagonal shape of a tennis racquet.

[0037]FIG. 8 shows a further cover 36B mounted over the handle portionof tool such as hammer 48. As illustrated, the cover 36B is applied intape form and would conform to the shape of the handle portion of hammer48. Other forms of covers could also be applied rather than using atape. Similarly, the tape could be used as a means for applying a coverto other types of implements.

[0038]FIG. 9 illustrates a cover 36C mounted over the end of ahandlebar, such as the handlebar of various types of cycles or any otherdevice having a handlebar including steering wheels for vehicles and thelike. FIG. 9 also illustrates a variation where the cover 36C has anouter contour with finger receiving recesses 52. Such recesses couldalso be utilized for covers of other types of implements.

[0039]FIG. 10 illustrates a variation of the invention where the cover36D is mounted to the handle portion of an implement 54 with the extremeend 56 of the implement being bare. This illustration is to show thatthe invention is intended to provide a vibration dampening grippingcover for the handle of an implement and that the cover need not extendbeyond the gripping area. Thus, there could be portions of the implementon both ends of the handle without having the cover applied to thoseportions.

[0040] In a preferred practice of the invention, as previouslydiscussed, a force dissipating stiffening layer is provided as anintermediate layer of a multilayer laminate where there is at least oneinner layer of vibration dampening material and an outer layer ofgripping material with the possibility of additional layers of vibrationdampening material and force dissipating layers of various thickness. Asnoted the force dissipating layer could be innermost. The invention mayalso be practiced where the laminate includes one or more layers inaddition to the gripping layer and the stiffening layer and thevibration dampening layer. Such additional layer(s) could beincorporated at any location in the laminate, depending on its intendedfunction (e.g., an adhesive layer, a cushioning layer, etc.).

[0041] The force dissipating layer could be incorporated in the laminatein various manners. FIG. 11, for example, illustrates a forcedissipating stiffening layer 58 in the form of a generally imperforatesheet. FIG. 12 illustrates a force dissipating layer 60 in the form ofan open mesh sheet. This is a particularly advantageous manner offorming the force dissipating layer where it is made of Kevlar® fibers.FIG. 13 illustrates a variation where the force dissipating layer 62 isformed from a plurality of individual strips of material 64 which areparallel to each other and generally identical to each other in lengthand thickness as well as spacing. FIG. 14 shows a variation where theforce dissipating layer 66 is made of individual strips 68 of differentsizes and which could be disposed in a more random fashion regardingtheir orientation. Although all of the strips 68 are illustrated in FIG.14 as being parallel, non-parallel arrangements could also be used.

[0042] The vibration dampening grip cover of this invention could beused for a wide number of implements. Examples of such implementsinclude athletic equipment, hand tools and handlebars. For example, suchathletic equipment includes bats, racquets, sticks, javelins, etc.Examples of tools include hammers, screwdrivers, shovels, rakes, brooms,wrenches, pliers, knives, handguns, air hammers, etc. Examples ofhandlebars include motorcycles, bicycles and various types of steeringwheels.

[0043] A preferred practice of this invention is to incorporate a forcedissipating layer, particularly an aramid, such as Kevlar® fiber, into acomposite with at least two elastomers. One elastomer layer wouldfunction as a vibration dampening material and the other outer elastomerlayer which would function as a gripping layer. The outer elastomerlayer could also be a vibration dampening material. Preferably, theouter layer completely covers the composite.

[0044] There are an almost infinite number of possible uses for thecomposite of laminate of this invention. In accordance with the varioususes the elastomer layers may have different degrees of hardness,coefficient of friction and dampening of vibration. Similarly, thethicknesses of the various layers could also vary in accordance with theintended use. Examples of ranges of hardness for the inner vibrationdampening layer and the outer gripping layer (which may also be avibration absorbing layer) are 5-70 Durometer Shore A. One of the layersmay have a range of 5-20 Durometer Shore A and the other a range of30-70 Durometer Shore A for either of these layers. The vibrationdampening layer could have a hardness of less than 5, and could even bea 000 Durometer reading. The vibration dampening material could be agel, such as a silicone gel or a gel of any other suitable material. Thecoefficient of friction as determined by conventional measuringtechniques for the tacky and non-porous gripping layer is preferably atleast 0.5 and may be in the range of 0.6-1.5. A more preferred range is0.7-1.2 with a still more preferred range being about 0.8-1. The outergripping layer, when also used as a vibration dampening layer, couldhave the same thickness as the inner layer. When used solely as agripping layer the thickness could be generally the same as theintermediate layer, which might be about {fraction (1/20)} to ¼ of thethickness of the vibration dampening layer.

[0045] The grip cover of this invention could be used with variousimplements as discussed above. Thus, the handle portion of the implementcould be of cylindrical shape with a uniform diameter and smooth outersurface such as the golf club handle 38 shown in FIG. 4. Alternatively,the handle could taper such as the bat handle shown in FIGS. 1-2. Otherillustrated geometric shapes include the octagonal tennis racquet handle38A shown in FIG. 7 or a generally oval type handle such as the hammer48 shown in FIG. 8. The invention is not limited to any particulargeometric shape. In addition, the implement could have an irregularshape such as a handle bar with finger receiving depressions as shown inFIG. 9. Where the outer surface of the implement handle is of non-smoothconfiguration the inner layer of the cover could press against andgenerally conform to the outer surface of the handle and the outermostgripping layer of the cover could include its own finger receivingdepressions. Alternatively, the cover may be of uniform thickness of ashape conforming to the irregularities in the outer surface of thehandle.

[0046] Other variations and uses will be readily apparent to those ofordinary skill in the art in view of the above teachings, examples andsuggestions.

What is claimed is:
 1. A vibration absorbing grip cover for covering ahandle of an implement comprising a premolded sleeve, said sleeve havingan upper end and a lower end, said upper end being open to permit saidsleeve to be inserted over and around the handle of the implement, saidsleeve being made of an elastomeric vibration dampening material, saidsleeve having a tacky outer surface to facilitate a user gripping thehandle during use of the implement, and said lower end of said sleevehaving an outwardly extending peripheral knob to act as a stop memberfor resisting the hand of a user from sliding off the handle during useof the implement.
 2. The cover of claim 1 wherein the inner surface ofsaid lower end of said sleeve is recessed having a contour conforming tothe outer surface of said knob for fitting over a knob at the end of theimplement handle.
 3. The cover of claim 2 in combination with a baseballbat having a knob at one of its ends, and said cover being fitted oversaid baseball bat with said knob of said bat disposed in said knob ofsaid cover.
 4. The cover of claim 1 wherein the thickness of said sleeveat said lower end is greater than the thickness of said sleeve at theremaining portion of said sleeve.
 5. The cover of claim 4 in combinationwith an implement having a handle, said handle terminating in an endwhich is free of any knob, and said sleeve being mounted over saidhandle.
 6. The combination of claim 5 wherein said implement is anarticle of athletic equipment.
 7. The combination of claim 6 whereinsaid implement is a tool.
 8. The combination of claim 6 wherein saidimplement is a handlebar.
 9. The cover of claim 1 wherein said sleeve isof single layer construction made from silicone material.
 10. The coverof claim 1 wherein said sleeve is a multilayer laminate, and saidmultilayer laminate including an inner layer of vibration absorbingmaterial and an outermost layer of tacky gripping material.
 11. Thecover of claim 10 including a further inner layer made from forcedissipating stiffening material.
 12. The cover of claim 11 wherein saidforce dissipating material is an aramid material.
 13. The cover of claim12 wherein said aramid material is a layer in open mesh form.
 14. Thecover of claim 12 wherein said outer gripping layer is made of vibrationabsorbing material.
 15. The cover of claim 1 wherein said sleeve tapersinwardly from said upper end to said lower end at the location of saidknob.
 16. In an implement having a handle with a gripping area, theimprovement being in a vibration resistant cover over said grippingarea, said cover being a multilayer laminate having at least an innerlayer and an outer layer, said inner layer being made of an elastomericvibration dampening material, and said outer layer being made of anelastomeric material having a tacky outer surface to facilitate thegripping of the handle.
 17. The implement of claim 16 wherein saidvibration dampening material is silicone, said outer layer being made ofa thermoplastic material different than said inner layer, and said innerlayer being thicker than said outer layer.
 18. The implement of claim 16including an intermediate force dissipating stiffening layer betweensaid inner layer and said outer layer, said intermediate layer beingmade of an aramid material, and said intermediate layer being thinnerthan said inner layer.
 19. The implement of claim 18 wherein said aramidlayer is of open mesh form.
 20. The implement of claim 16 including atleast one further inner layer, and said at least one further inner layerbeing a thin layer made of force dissipating stiffening material. 21.The implement of claim 20 wherein said force dissipating stiffeningmaterial is an aramid material.
 22. The implement of claim 21 whereinsaid aramid material is of mesh form.
 23. The implement of claim 21wherein said inner layer is made of silicone and is the innermost layer,said outer layer being made of a thermoplastic material, and saidsilicone layer being thicker than said thermoplastic outer layer. 24.The implement of claim 21 wherein said inner layer is made of a siliconegel and is the innermost layer, and said outer layer is made of asilicone gel.
 25. The implement of claim 20 wherein said cover isapplied over said gripping area in tape form.
 26. The implement of claim20 wherein said laminate includes at least four layers.
 27. Theimplement of claim 20 wherein said implement is an article of athleticequipment.
 28. The implement of claim 20 wherein said implement is atool.
 29. The implement of claim 20 wherein said implement is ahandlebar.
 30. The implement of claim 16 wherein said implement is anarticle of athletic equipment.
 31. The implement of claim 16 whereinsaid implement is a tool.
 32. The implement of claim 16 wherein saidimplement is a handlebar.